Field of the Invention
The present invention relates to vibration suppression of a lens barrel (a column) in a charged particle beam apparatus and particularly relates to a charged particle beam apparatus and a vibration damper for a charged particle beam apparatus with which it is possible to achieve vibration suppression of a plurality of columns.
Background Art
A charged particle beam apparatus such as an electron microscope is an apparatus that irradiates a sample with an electron beam (charged particle beam) and that detects charged particles obtained on the basis of the irradiation. The charged particle beam apparatus is provided with a plurality of optical elements for beam control and a beam passing through the optical elements is converged and deflected. The beam adjusted by the optical elements reaches the sample or a position near the sample and a signal corresponding to the state of a position that the beam reaches is detected by a detector or the like. In order to reduce an influence of vibration on such a charged particle beam apparatus, Japanese Patent No. 5524229 (corresponding to U.S. Pat. No. 8,729,467) discloses a technique of damping vibration of a column by providing a tension rod-shaped structure member, into which a viscoelastic sheet is built, between the column and a top plate. In addition, Japanese Patent No. 5364462 (corresponding to U.S. Pat. No. 8,629,410) discloses a technique in which a structure such as an ion pump that is additionally attached to a column is supported by a pillar with a viscoelastic sheet being interposed therebetween. In addition, WO 99/27570 (corresponding to U.S. Pat. No. 6,529,264) discloses a technique in which each of optical lens barrels, which are disposed to be parallel with each other, is divided into two parts and an optical path between lens barrels is used as a supporting rod between the lens barrels in a semiconductor exposure apparatus.